Shears employed on heavy construction machinery include a pair of jaws with one or more blades positioned thereon. The jaws may include a pivoting jaw and a fixed jaw. The jaws may be mounted on a pivot pin such that the one of the jaws may be pivotable relative to a fixed jaw therein. The pivoting jaw moves the associated blade with respect to the blade on the fixed jaw to provide shearing and crushing forces to an object. Such shears may further employ shim plates and low-friction plates mounted on the pivot pin and adjacently located to each of the jaws. The shim plates are configured to maintain a pre-determined amount of tolerance between the jaws while the low-friction plates serve to reduce friction between the jaws during operation.
During an operation of the shear, the jaws may be opened and closed several times to accomplish shearing of objects. However, upon frequent opening and closing of the jaws over a prolonged period of time, the shim plates and the low-friction plates may be subject to wear from the jaws. This wear may cause a slack in the shim plates and the low-friction plates thus rendering the pivotable jaw susceptible to slide or wobble on the pivot pin during operation. Therefore, subsequent use of the shear thereafter may entail an increased amount of effort from the jaws to accomplish the shearing or crushing of the objects.
One way of compensating for slack in the plates stacked and disposed on the pivot pin is to replace the plates. However, replacing the plates altogether may require operating personnel to disassemble the jaws and re-insert new plates. Further, additional costs are incurred by way of replacement and downtimes of the shear. Furthermore, this method may be tedious and cumbersome while also requiring expensive tools to pivotally unfasten and re-fasten the jaws to each other.
U.S Published Application 2011/0225829 ('829 application) discloses a heavy duty, configurable shear/crusher demolition tool having an upper jaw, a lower jaw, and a pivot group connecting the upper jaw and the lower jaw. A configurable number of tooth holders are mounted on the upper jaw and the lower jaw. A configurable number of teeth are removably mounted to the tooth holders. A configurable number of shear blade holders are mounted on the upper jaw and the lower jaw. A configurable number of shear blades are removably mounted to the shear blade holders.